00:01
So we're going to be following these chromosomes in the very basic look at its life cycle.
00:05
So we're going to start with someone who is just a normal person, and we see that they have their two chromosomes here that are in part of g phase, and their chromosomes are unreplicated.
00:23
But you see that there's sort of two sides to each of these chromosomes, because they are sister chromatids.
00:40
And so if one of these genes holds, you know, alleles a and b, one of the chromosomes holds genes a and b, and the other one holds c and d, then you see that the sister chromatids, right, there will be two alleles for each gene.
01:03
So however many genes you have, you are going to have two alleles for each gene at this state.
01:10
Because they're put into these sister chromatids pairs.
01:14
But a little later on, when a cell gets a signal that it's time to reproduce and it's time to make more cells, then we will end up with cells that do experience recombination, or sorry, replication.
01:33
And now we have a situation like this, where we still have these chromosomes with sister chromatids, but we now have pairs of them.
01:40
And so these are going to be called homologous pairs.
01:46
This is in preparation for the cell to split.
01:50
And so when it does, when it goes through meiosis 1, we're going to have two different daughter cells and each one gets one pair of sister chromatids for the big gene or for the big chromosome and one for the little one...